Javascript 类型 'Observable<Object>' 不可分配给类型 'Observable<IUser[]>'
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Type 'Observable<Object>' is not assignable to type 'Observable<IUser[]>'
提问by Sam Kelham
In my Api service I have this simple getUsersfunction to fetch all of the users on the api.
在我的 Api 服务中，我有一个简单的getUsers函数来获取 api 上的所有用户。
public getUsers(url: string): Observable<IUser[]> {
return this._http.get(url);
}
This is my IUser interface, I have made all the field optional for now.
这是我的 IUser 界面，我现在已将所有字段设为可选。
export interface IUser {
id?: string;
first_name?: string;
last_name?: string;
location?: string;
followers?: string;
following?: string;
checkins?: string;
image?: string;
}
and here is how I have used the service in my component:
这是我在组件中使用该服务的方式：
export class SocialOverviewContainerComponent implements OnInit {
public userData = [];
public showForm = {};
private _apiService: ApiService;
constructor(apiService: ApiService) {
this._apiService = apiService
}
public ngOnInit(): void {
this.getUsersData();
}
public getUsersData() {
this._apiService.getUsers(ApiSettings.apiBasepath + 'users/')
.subscribe(users => {
this.userData = users;
})
}
}
and this is is the Type error I get when it compiles
这是我在编译时遇到的类型错误
ERROR in src/app/services/api.service.ts(18,5): error TS2322: Type 'Observable<Object>' is not assignable to type 'Observable<IUser[]>'.
Type 'Object' is not assignable to type 'IUser[]'.
The 'Object' type is assignable to very few other types. Did you mean to use the 'any' type instead?
Property 'includes' is missing in type 'Object'.
I thought this might be because my response doesn't match the interface, which I have double check and it does. And I have also made the field optional for now to make sure.
我认为这可能是因为我的响应与界面不匹配，我已经仔细检查过，确实如此。我也暂时将该字段设为可选以确保。
I know I can fix this by casting the observable as any, but doesn't that defeat the point of using Typescript?
我知道我可以通过将 observable 投射为 any 来解决这个问题，但这难道不会破坏使用 Typescript 的意义吗？
Any help on where I am going wrong would be great
对我哪里出错的任何帮助都会很棒
Thanks in advance
提前致谢
回答by th3n3wguy
There are two ways to do this, and it depends on which version of RxJS / Angular that you are using. Here are the two ways to do it depending on your versions:
有两种方法可以做到这一点，这取决于您使用的是哪个版本的 RxJS / Angular。以下是两种方法，具体取决于您的版本：
// Using RxJS v4 / Angular v2-4. I assume that you're using the HttpModule...
import 'rxjs/add/operator/map';
public getUsers(url: string): Observable<IUser[]> {
return this._http.get(url)
.map((response: Response) => <IUser[]>response.json());
}
// Using RxJS v5 / Angular 5+ (at the moment). I assume that you're using the HttpClientModule, as the HttpModule was deprecated in Angular v4.
public getUsers(url: string): Observable<IUser[]> {
return this._http.get<IUser[]>(url);
}回答by Sam Kelham
Typical, that 5 mins after I post, I find a solution.
通常，在我发布后 5 分钟，我找到了解决方案。
Trick was to cast the .getfunction in the service the same as the type on the getUsersfunction as below:
技巧是.get将服务中的getUsers函数与函数上的类型相同，如下所示：
public getUsers(url: string): Observable<IUser[]> {
return this._http.get<IUser[]>(url);
}
Hope this helps other people out as well
希望这也能帮助其他人
回答by Avinash Barnwal
in my case the below worked
在我的情况下，下面的工作
getUsers(): Observable<User[]> {
return <Observable<User[]>> this.http.get(this.pathAPI + 'user', super.header())
.pipe(catchError(super.handleError));
}
I am using Angular 6
我正在使用 Angular 6
